1. Field of the Invention
The present invention relates to an image input device which can be directly connected to an image output device without any intervention of a printer server such as a personal computer and its control method, and an image input/output system.
2. Related Background Art
Along with the spread of digital image sensing devices such as digital cameras, digital video cameras, and the like, techniques that can facilitate handling of digital image sensing devices have been developed. As one of these techniques, a direct connection between a digital image sensing device and a printer is known. With this technique, an image sensed by a digital image sensing device can be directly printed by a printer without intervention of any personal computer or the like. For this reason, the direct connection between the digital image sensing device and printer promotes use of digital cameras by users who have no personal computers.
A connection between a digital image sensing device and personal computer or a connection between the digital image sensing device and printer upon direct printing is realized by one of wireless and wired methods. Both of the methods consume much of the battery of the digital image sensing device to transfer data from the digital image sensing device, to check an image on a viewfinder of the digital image sensing device, and so on. That is, upon data transfer to a personal computer or direct printing, the user must connect two cables, i.e., a cable for data transfer and an AC adapter for supplying electric power to the camera.
The present invention has been made in consideration of the above-mentioned prior art, and has as its object to obviate the need for connecting a power supply line to a digital image sensing device upon data transport and to prevent battery consumption or short battery during the transport.
In order to achieve the above object, the present invention comprises the following arrangement.
That is, there is provided an image input/output system built by connecting an image output device and an image input device,
the image output device outputting an image signal received from the image input device, and supplying electric power to the image input device, and
the image input device being connected to the image output device via a connection cable to transmit image data to the image output device and to receive the electric power supplied from the image output device, and having a power supply unit, and a power supply control unit for determining whether to receive the electric power from the image output device, for, when it is determined that the image input device can receive the electric power from the image output device, using the electric power from the image output device, and for, when it is determined that the image input device cannot receive the electric power from the image output device, using electric power from the power supply unit.
There is also provided an image input device comprising:
connection means connected to an external apparatus which exchanges data with a connected device, and can supply electric power to the device;
a power supply unit; and
a power supply control unit for checking if electric power can be received from the external device, for, when it is determined that the electric power can be received from the external device, using the electric power from the external device, and for, when it is determined that the electric power cannot be received from the external device, using electric power from the power supply unit.
Furthermore, there is provided a method of controlling an image input device, which has a power supply unit, is connected to an external device, and is driven by electric power supplied from one of the external device and the power supply unit, comprising:
a determination step of checking if electric power can be received from the external device; and
a power supply control step of using the electric power from the external device when it is determined that the electric power can be received from the external device, and using electric power from the power supply unit when it is determined that the electric power cannot be received from the external device.
Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof.